In 1975, NRL developed the Central Atmosphere Monitor System (CAMS), which allowed submarine crews, for the first time, to reliably monitor the air aboard their boats. CAMS is a combination carbon dioxide detector and fixed-collector mass spectrometer that monitors hydrogen, water, nitrogen, carbon monoxide, oxygen, carbon dioxide, and refrigerant gases. The system became the first submarine air monitor to be "service approved" and was subsequently installed on all U.S. Navy nuclear submarines. NASA also uses a variant of this system for manned space vehicles.